Process for the production of grain oriented magnetizable strips and sheets



United States l ate'nt 3,008,857 PROCESS FOR THE PRODUCTION OF GRAIN ORIENTED MAGNETIZABLE STRIPS AND SHEETS Hans-Eberhard Miibius, Altena, Westphalia, Germany,

assignor to Vereinigte Deutsche Metallwerke Aktiengesellschaft, Frankfurt am Main-Heddernheim, Germany No Drawing. Filed Feb. 7, 1958, Ser. No. 713,806 Claims priority, application Germany Feb. 16, 1957 5 Claims. (Cl. 148-111) The present invention relates to improvements in the production of strips and sheets from silicon and/or aluminum containing iron alloys having grain oriented textures which preferentially canbe magnetized in the rolling direction or preferentially magnetized not only in the rolling direction but also in the direction transverse thereto. These textures are respectively generally known as the (110) [001] texture or Goss texture and th (100) [001] texture or Cube texture.

In order to produce the above textures and properties in strips and sheets they are treated in a known manner employing certain rolling and annealing conditions. The measures previously employed, however, have ,not sufr ficed to produce uniformly good grain oriented structure in the strips and sheets produced. As a consequence of the variability of the quality of grain orientation obtained, a relatively wide spread of wattage losses results.

It has been found according to the invention that it-is advisable to employ an ageing step to avoid this disadvantage. The ageing expediently is carried out immediately after the last cold rolling and can be carried out either at room temperatureor at elevated temperature. It is of advantage to age at as low temperatures as possible, as at high temperatures the phenomena which favorably atfect the texture proceed so rapidly that they cannot be controlled with certainty. It was therefore found advantageous to select a temperature not over 300 0., preferably not over 100 C., for such ageing treatment. With an ageing temperature of 100 C., an ageing period of 1 to 10 hours, preferably 3 to 6 hours, 'suffices. When ageing is carried out at room temperature, considerably longer ageing periods come into consideration which may stretch over several days, preferably 2 to 10 days.

In the event that the final anneal is not carried out immediately after the ageing, it has been found desirable to cool the sheets or strips to about 0 C. or lower and to maintain them at such low temperature until the final anneal is effected. Also, in some instances it may be advisable to maintain the cold rolled stock at such low temperatures before the ageing treatment if it is not convenient to carry out the ageing treatment immediately after the cold rolling. i

The cold rolled strip or sheet material can, for example, be aged by letting it stand after completion of the cold rolling at temperatures between 20 and 35 C. for 2 to 10 days and only thereafter subjecting it to the final anneal. It is also possible, for example, to place the sheet or strip material after completion of the cold rolls ing directly into the oven which is to be employed for the final anneal while still warm from a previous anneal and to wait for a certain period of time dependent upon the temperature of the Warm oven before beginning the heating for the final anneal or an anneal preceding such final anneal. For example, an ageing within the purview of the invention is accomplished when the temperature of the oven is 100 C. and the sheet or strip to be aged is subjected to this temperature for. 10 hours or when The silicon content in the case of magnetic silicon iron alloys can be between 0.5 to 3.5% and preferably should be between 1.8 to 3.2%, the aluminum content in the case of magnetic aluminum iron alloys can be between 0.5 and 2.5% and preferably should be between 1.0 to

1.5%, and in the case of magnetic silicon-aluminum iron alloys thesum of the quantities of silicon and aluminum can be between 0.5 and 3.5 and preferably should be between 1.0 and 3.2%. I g

The alloys treated according to the invention, as is customary in high quality alloys for magnetic purposes, may contain a small metalloid content, for instance, sulfur up to 0.03%, phosphorus up to 0.03% and carbon up to 0.05%. If the starting alloy does not have a sufficiently low metalloid content after the customary hot rolling .treatment is should be given a refining anneal under hydrogen'or vacuum in order to reduce its metalloid con tent to the necessary degree before the cold rolling.

The alloys employed according to the invention can, if desired, also contain nickel in small quantities, for example, up to 1%, such as in amounts of 0.1-1%. The nickel can also be wholly or partly replaced by one or more other metals, such as chromium, cobalt, manganese, copper, .zinc and vanadium,- whose atom diameter is as close as possible to that of iron.

The following examples will serve to illustrate several '7 embodiments of the process according to the invention:

Example 1 jected to a refining anneal and then cold rolled to a thickness of 105mm. After an intermediate anneal, it was then cold rolled to a final thickness of 0.25 mm. Directly after finishing the cold rolling, the strip was aged for 6 hours at 100 C. Thereafter the strip was raised-to a temperature of l250 C. in 15 hours, maintained at this temperature for 12 hours and then cooled to room temperature in 94 hours. 92 vol. percent of the resulting strip was oriented in the cube texture.

Example 2 The procedure of Example 1 was repeated with another sample of the same alloy with the exception that the ageing between the cold rolling and final anneal was omitted in that upon completion of the cold rolling to a thickness of 0.25 mm. the strip was immediately placed in the annealing oven and treated therein as described in Example 1. Only 73 vol. percent of the resulting strip was oriented in the cube texture.

Example 3 A cold rolled strip produced from the same iron alloy as used in Example 1 in the manner described in Example 1 was subjected to ageing at 20 C. for 9 days and then heated to 1250? C. in 15 hours, maintained at this temperature for 12 hours and then cooled to room tenn perature in 96 hours. 94 vol. percent of the resulting strip was oriented in the cube texture.

Example 4 An iron alloy with 2.1% silicon was hot rolled in the customary manner to a stirp 1.5 mm. thick. The strip was then cold rolled in one stage in 8 passes to a thickness of 0.30 mm., (an reduction). The cold rolling was unidirectional. After the cold rolling the strip.

was held for 4 days at 10 C. and thereafter aged for 1 hour at 200 C. Thereafter it Was held for a further 40 hours at l0 C. before being given the final anneal at 1250 C. .82 vol. percent of the strip thus obtained was oriented in the cube texture.

Example 5 An iron alloy containing 3.1% of silicon was hot rolled in the customary manner to a strip 3.2 mm. thick, then cold rolled without an intermediate anneal to athickness of 0.8 mm. After an intermediate'anneal it was then cold rolled to a final thickness of 0.3 mm. Directly thereafter the cold rolled strip was subjected to ageing at 100 C. for 3 hours. The aged strip was then cold rolled to a final thickness of 0.3 mm. Directly thereafter the cold rolled strip was subjected. to ageing at 100 C. for three hours. The aged strip was then heated to 1250 C. in 15 hours, maintained at this temperature for 12 hours and then cooled to room temperature in 94 hours. 20 vol. percent of the finished stripwas oriented in the Goss texture and 75% thereof was oriented in the cube texture.

Example 6 The procedure of Example 5 was repeated with another sample of the same alloy with the exception that the ageing between the cold rolling and the final anneal was omitted in that upon completion of the cold rolling to a thickness of 0.3 mm. the strip was immediately placed in the annealing oven and treated therein as described in Example 5. The finished strip did not possess as good an orientation as that of Example 5 as 45 vol. percent of the finished strip was oriented in the Goss texture and 20 vol. percent thereof was oriented in the cube texture.

This application is a continuation-in-part of my application Serial No. 701,712, filed December 10, 1957.

I claim:

1. In a process for the production of pronounced (100) [001] texture in magnetizable sheets and strips of magnetizable iron alloys selected from the group consisting of magnetizable silicon iron alloys containing 0.5 to 3.5% of silicon, magnetizable aluminum iron alloys containing 0.5 to 2.5% of aluminum and magnetizable silicon-aluminum iron alloys in which the content of silicon aluminum is from 0.5 to 3.5% in which hot rolled sheets and strips are cold rolled and then subjected to a final recrystallization anneal, in combination therewith, the step which comprises subjecting the cold rolled stock to a predetermined ageing for a predetermined period of time at a predetermined temperature between the cold rolling and the final recrystallization anneal the temperature and duration of such predetermined ageing being such as to cause an improvement in the quality of the (100) [001] grain orientation achieved upon the final recrystallization anneal and ranging from room temperature for a period of 2 to 10 days to 100 C. for a period of about 1 to 10 hours.

2. The process of claim,1 comprising in addition maintaining said stock at a temperature up to C. during any period of time between the cold rolling and the final recrystallization anneal which is not taken up by the ageing treatment.

3. In a process for the production of pronounced (100) [001] texture in magnetizable sheets and strips of magnetizable iron alloys selected from the group consisting of magnetizable silicon iron alloys containing 0.5 to 3.5% of silicon, magnetizable aluminum iron alloys containing 0.5 to 2.5% of aluminum and magnetizable silicon-aluminum iron alloys in which the content of silicon aluminum is from 0.5 to 3.5% in which hot rolled sheets and strips are cold rolled and then subjected to a final recrystallization anneal, in combination therewith, the step which comprises subjecting the cold rolled stock to a predetermined ageing for a predetermined period of time at a predetermined temperature between the cold rolling and the final recrystallization anneal, the temperature and duration of such predetermined ageing being such as to cause an improvement in the quality of the [001] grain orientation achieved upon the final recrystallization anneal, said ageing being effected at room temperature for 2 to 10 days.

4. In a process for the production of pronounced (100) [001] texture in magnetizable sheets and strips of magnetizable iron alloys selected from the group consisting of magnetizable aluminum iron alloys containing 0.5 to 3.5 of silicon, magnetizable aluminum iron alloys containing 0.5 to 2.5% of aluminum and magnetizable silicon-aluminum iron alloys in which the content of silicon aluminum is from 0.5 to 3.5% in which hot rolled sheets and strips are cold rolled and then subjected to a final recrystallization anneal, in combination therewith, the step which comprises subjecting the cold rolled stock to a predetermined ageing for a predetermined period of time at a predetermined temperature between the cold rolling and the final recrystallization anneal, the temperature and duration of such predetermined ageing being, such as to cause an improvement in the quality of the (100) ['001] grain orientation achieved upon the final recrystallization anneal, said ageing being efiected at 100 C. for about 1 to 10 hours. 5. In a process for the production of pronounced (100) [001] texture in magnetizable sheets and strips of magnetizable iron alloys selected from the group consisting of magnetizable silicon iron alloys containing 0.5 to 3.5% of silicon, magnetizable aluminum iron alloys containing 0.5 to 2.5 of aluminum and magnetizable silicon-aluminum iron alloys in which the content of silicon aluminum is from 0.5 to 3.5% in which hot rolled sheets and strips are cold rolled and then subjected to a final recrystallization anneal, in combination therewith, the step which comprises subjecting the cold rolled stock to a predetermined ageing for a predetermined period of time at a predetermined temperature between the cold rolling and the final recrystallization anneal, the temperature and duration of such predetermined ageing being such as to cause an improvement in the quality of the (100) [001] grain orientation achieved upon the final recrystallization anneal, said ageing being effected at 100 C. for 3 to 6 hours.

References Cited in the file of this patent UNITED STATES PATENTS 2,112,084 Frey et al. Mar. 22, 1938 2,875,114 Albert Feb. 24, 1959 2,943,007 Walker et al. June 28, 1960 OTHER REFERENCES Metallurgical Dictionary, by J. G. Henderson, 1953, pp. 7-8.

Metal T reatment and Drop Forging, vol. 20, November 1953, pp. 557-559 and 562, by Leak et al.

Journal of the Iron and Steel Institute, November 1952, pp. 301-306, by Cottrell et al. 

1. IN A PROCESS FOR THE PRODUCTION OF PRONOUNCED (100) (001) TEXTURE IN MAGNETIZABLE SHEETS AND STRIPS OF MAGNETIZABLE IRON ALLOYS SELECTED FROM THE GROUP CONSISTING OF MAGNETIZABLE SILICON IRON ALLOYS CONTAINING 0.5 TO 3.5% OF SILICON, MAGNETIZABLE ALUMINUM IRON ALLOYS CONTAINING 0.5 TO 2.5% OF ALUMINUM AND MAGNETIZABLE SILICON-ALUMINUM IRON ALLOYS IN WHICH THE CONTENT OF SILICON + ALUMINUM IS FROM 0.5 TO 3.5% IN WHICH HOT ROLLED SHEETS AND STRIPS ARE COLD ROLLED AND THEN SUBJECTED TO A FINAL RECRYSTALLIZATION ANNEAL, IN COMBINATION THEREWITH, THE STEP WHICH COMPRISES SUBJECTING THE COLD ROLLED STOCK TO A PREDETERMINED AGEING FOR A PREDETERMINED PERIOD OF TIME AT A PREDETERMINED TEMPERATURE BETWEEN THE COLD ROLLING AND THE FINAL RECRYSTALLIZATION ANNEAL THE TEMPERATURE AND DURATION OF SUCH PREDETERMINED AGEING BEING SUCH AS TO CAUSE AN IMPROVEMENT IN THE QUALITY OF THE (100) (001) GRAIN ORIENTATION ACHIEVED UPON THE FINAL RECRYSTALLIZATION ANNEAL AND RANGING FROM ROOM TEMPERATURE FOR A PERIOD OF 2 TO 10 DAYS TO 100* C. FOR A PERIOD OF ABOUT 1 TO 10 HOURS. 